spacetoday.net: Herschel space telescope ends mission

Posted: Tue, Apr 30, 2013, 7:58 AM ET (1158 GMT)
Herschel space telescope (ESA)

ESA's Herschel infrared space telescope formally ended its mission Monday when it exhausted its remaining supply of liquid helium coolant, the space agency announced. ESA had warned for weeks that Herschel would soon run out of liquid helium, ending operations, and telemetry from the spacecraft Monday indicated rising temperatures in instruments caused by the exhaustion of that coolant supply. Herschel, launched in May 2009, lasted longer than expected, returning 25,000 hours of observations at infrared wavelengths. Herschel had been operating at the Earth-Sun L2 point, 1.5 million kilometers from the Earth; controllers will command the spacecraft to move into a stable orbit around the Sun before shutting it down.